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Synthesis 2006(16): 2625-2639  
DOI: 10.1055/s-2006-942490
REVIEW
© Georg Thieme Verlag Stuttgart · New York

Ring-Closure Reactions of ortho-Vinyl-tert-anilines and (Di)Aza-Heterocyclic Analogues via the tert-Amino Effect: Recent Developments

Péter Mátyus*, Olivér Éliás, Pál Tapolcsányi, Ágnes Polonka-Bálint, Beáta Halász-Dajka
Department of Organic Chemistry, Semmelweis University, and Szentágothai Knowledge Center, Hőgyes E. u.7., 1095 Budapest, Hungary
Fax: +36(1)2170851; e-Mail: peter.matyus@szerves.sote.hu ;
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Publikationsverlauf

Received 28 February 2006
Publikationsdatum:
13. Juli 2006 (online)

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Abstract

One version of the tert-amino effect operating in tert-anilines possessing an ortho-vinyl substituent affords a fused tetrahydropyridine ring by an isomerization process with the formation of a new carbon-carbon bond between the vinyl and tert-amino moieties. Since its discovery in 1984, this type of cyclization has been efficiently used for the construction of fused-ring systems. However, it has been found that the electron-deficient heterocyclic analogues of tert-anilines, such as diazines, may undergo isomerization at considerably lower reaction rates and, as a consequence, their reactions may require harsh conditions. Recent synthetic studies have indicated that the rate and yield may be improved by incorporating the β-vinylic carbon atom into an electron-deficient ring and/or buttressing the tert-amino group, and/or performing the reaction by means of microwave irradiation.

This review describes relatively recent synthetic transformations involving this type of tert-amino effect and devotes special attention to structure-reactivity relationships including regio- and stereo­chemical aspects.

  • 1 Introduction

  • 2 The tert-Amino Effect: Type 2 Reactions

  • 2.1 Substrates with a Dicyanovinyl Group

  • 2.1.1 Benzene Derivatives

  • 2.1.2 Pyridine Derivatives

  • 2.1.3 Pyrimidine Derivatives

  • 2.1.4 Pyridazine Derivatives

  • 2.2 Substrates with a Cyclic Vinyl Substituent

  • 2.2.1 Pyridazine Derivatives

  • 2.2.2 Pyrimidine Derivatives

  • 2.2.3 Benzene Derivatives

  • 2.3 Microwave-Assisted Synthesis

  • 2.4 Regio- and Stereochemical Features

  • 3 Conclusions

Key words

tert-amino effect - ring closure - isomerization - substituent effects - spiro compounds - heterocycles - microwave-assisted synthesis

7

Mátyus, P.; Bálint-Polonka, Á. unpublished results.

14

Halász-Dajka, B.; Mátyus, P. unpublished results.

24

Mátyus, P.; Éliás, O. manuscript in preparation.